Running premix instead of separate oil tank

Discussion in 'General Tuning' started by ReceivaL, Jan 29, 2017.

  1. ReceivaL

    ReceivaL Aprilia SR 125

    Messages:
    18
    My Aprilia has oil pump oil objected what ever you like to call it heard different things anyway can I just simply empty my oil tank completely and premix my fuel and put to straight in my petrol tank? I've seen videos on YouTube but looks complicated to remove it and bypass it?

    So can I just run it on premix? It's Aprilia sr 125 1999

    Same engine and fuel system as gilera fxr and sp as far as I'm aware friend has sp 125 and all the exact same.
     
    ReceivaL, Jan 29, 2017
    #1
  2. MARSH

    MARSH Whooooo!

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    You could fit a new oil pump, it's not difficult.
     
    MARSH, Jan 29, 2017
    #2
  3. Tamiyacowboy

    Tamiyacowboy Pippa's Owner

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    you could go direct mix, but if you ever forget your up the shoot. i would as marsh says fit a new pump and be done that way, atleast its feeding the right amount when needed and would last a good few 10,000 miles more
     
    Tamiyacowboy, Jan 30, 2017
    #3
  4. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

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    to answer your question, yes, you can just not fill the oil tank and run oil in your fuel, i cut the drive belt befor now an jus pulled it out, pump dissabled. REMEMBER, when you run premix, your reducing the fuel by 2% as its been replaced with oil, so your jetting will be 2% leaner when running premix. so go up 2 sizes if you want it 100%... oil pumps bearly throw 100:1 at your engine mind.. so 50:1 (20ml per litre) is MORE than enough, too much oil does more damage with small high rpm engines
     
    MiNoR cOnFuSiOn, Feb 15, 2017
    #4
  5. markymark2

    markymark2 Member

    Messages:
    45
    premix is a better way of supplying the fuel oil mix and was only phased out starting in the 70`s to make 2 stroke ownership more user friendly , you don`t need to think too hard about which method will supply better mixed fuel oil , one where it has mixed in the tank so thoroughly that it is to all intensive purposes one liquid or the other where drops of oil are fed into the carb or intake manifold and sucked in to the crankcases together with the fuel , mixing at that stage , be careful with ratios there are very few running as lean as 100:1 , 50:1 these days is most common , BUT and t`s a big BUT on purpose (not like my GF , LOL.) if you start tuning mods and fitting 50/70cc sports kits your oil pump will not deliver enough oil to keep the engine from overheating and seizing because it has been set up to deliver specifically just the ratio needed by the stock engine , TNT make an adjustable oil pump but i`ve read many reviews saying it`s rubbish so pre-mix is the way to go if doing these type mods , check that the oil is for pre mix as some say they are suitable for both methods of mixing where vas others are for one or the other and don`t be a cheapskate when it comes to your choice of oil , go for at least a semi synthetic from Rock or any other reputable brand , fully synthetic is really the only one for anything more than a mildly tuned engine , be careful to read what the manufacturer of any cylinder kit says to use as far as ratio goes , my latest kit an Airsal 70cc requires minimum 30:1 as do many of the sports kits with high end ones at 25:1 , another benefit of premixing is that my old oil tank is now my reserve petrol tank all for about £10 just a Y connector for the fuel line and a petrol tap , another 20 miles to find a garage :)
     
    markymark2, Feb 16, 2017
    #5
  6. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

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    ignore manufactors of kits, if they specify 25:1 then the kits junk.. 50:1 is fine in any 2 stroke, even high end crossers that state 33:1 are playing it safe.

    oh and i have always run 70's with oil pumps just fine, set them to maximum delivery. no explosions, ride hard and long every day. i run semi synth rock oil and theres loads of signs of adiquate lubrication in the cylinder whenever i service the top end. cranks lovely and red.. same with premix, never more than 20ml per litre, too much oil is bad, gums everything up and with a high rpm engine (anything with a pipe) iut will loose power. its not a chainsaw, its not running low rpm and being DRAGGED down to almost no rpm at FULL load. its a bike. 50:1 has been fine for me since the 80's

    oh, and the trend towards oil pumps came when petrol stations stopped the dual sale of oil in "shots" when fuel was bought, largely due to the brand trending and oil avalability. as in, people wanted a specific oil now, not just the one in the shot pump at the petrol station. it IS more convenient to use a pump, but when they break, your piston grabs your cylinder and the back wheel tries to grab the road :D yay for auto clutches and short scary 60mph skids :D
     
    MiNoR cOnFuSiOn, Feb 26, 2017
    #6

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